This invention relates to clear, cold-stable liquid washing agent concentrates, particularly for washing textiles, containing potassium soaps, nonionic tensides, sulfonates and optical brighteners.
It is well known that the preparation of clear, aqueous washing agent concentrates that do not dissociate or solidify at low temperatures, particularly from below the freezing point to -10.degree. C., presents considerable problems. This applies especially to concentrates that contain soap and have a content of active substance of 50% by weight and more. Additional difficulties can occur when such agents contain optical brighteners. Phase separations or precipitates caused by low temperatures or freezing of the solutions frequently are irreversible, even after reheating. Either further dilution of the solutions or the use of larger quantities of organic solvents can be employed to meet such problems, but dilute solutions require more packing and transport volume, while large amounts of organic solvents introduce problems because of the higher costs and greater flammability associated with them.
German Published Application DE-OS 26 09 752, by which these problems are largely solved, describes a clear, liquid washing agent concentrate that is unaffected by cold, with a solids content of up to 55% by weight, containing 8% to 18% by weight of a potassium soap derived from fatty acids with 12 to 18 carbon atoms and consisting mainly of oleic acid, from 10% to 25% by weight of ethoxylated alcohols with 8 to 12 carbon atoms and an average of 5 to 10 ethylene glycol ether groups, as well as from 4% to 10% by weight of sodium alkylbenzenesulfonates with 10 to 14 carbon atoms in the alkyl group, from 0.05% to 1% of optical brighteners, and conventional solvents or solvents miscible with water, together with at least 45% of water.
Agents of this type are above all intended for use in large-scale laundries with automatic washing, drying and ironing equipment, in which the individual operations are joined into a continuous process. The composition of a washing agent suitable for this purpose must be formulated in such a manner that no disturbances occur that impair the functioning of the machines or interrupt the work rhythm. It has been observed with certain new automatic washing machines that the use of conventional washing agents and to a certain, but lesser, degree also the use of the agents according to DE-OS 26 09 752 reduces the necessary easy movability of the loading and unloading doors that move in grooves, so that these no longer open and close in the proper rhythm. Furthermore, problems may arise during water extraction and hot-mangling. For example, wash compacted in self-centrifuging washing machines can be loosened with the wall of the drum only with additional labor, or problems may arise during the transporting and mangling of the washing.